A 76-foot boat with a leaky hull sank Friday at the Ala Wai Small Boat Harbor despite efforts by the Honolulu Fire Department and the U.S. Coast Guard to pump water from the vessel.

Two units with eight firefighters responded to a 911 call of a boat docked at slip 664 taking on water just before 6:50 p.m. Thursday. HFD said the boat had been taking on water since Wednesday night due to a 6-inch hole in its hull.

Ross Reid, who works for the boat owner, said the Coast Guard assisted with pumping water out of the vessel Wednesday. He told KITV the vessel was built in the 1950s as a military minesweeper and later converted into a pleasure craft.

Neither the Coast Guard nor the boat owner could be reached for comment on the incident.

Firefighters used submersible pumps and generators to lower the water level in the sinking boat from about 3 feet to just a few inches so repairs could be made, according to HFD. Fire crews left the scene at about 8:40 p.m. Thursday.

Then at about 12:10 a.m. Friday, one unit with four firefighters responded to a second 911 call from the same slip to find the repairs made earlier had not stopped the leak. HFD said water in the boat had risen to about the same level as before.

A sheen on the water surface was seen above the sunken vessel Friday morning, and a strong odor of fuel permeated the air. An absorbent boom surrounded the vessel to control the spread of spilled fuel.

Reid estimated that 50 gallons of diesel fuel spilled into the water from the boat. He noted it quickly sank and that there was no time to remove the fuel.

“If we had the time, we would’ve pumped the diesel fuel out,” Reid said. “It all happened so quick.

“We barely had time to get everybody’s stuff off,” he said as he retrieved items he had managed to salvage from the vessel before it sank.

No injuries were reported.

Passersby at the boat harbor stopped in front of the slip to gawk at the submerged vessel on its side in the shallow water with a small section of the boat protruding from the surface.